1. Barnhard Lang, Gonzalo Angulo, and Eric Vauthey
Ultrafast Solvation Dynamics of Coumarin 153 in Imidazolium-Based Ionic Liquids
Barnhard Lang, Gonzalo Angulo, and Eric Vauthey
J.Phys.Chem.A 2006,
300文字/分
Miyasaka Lab.
Masayasu Muramatsu

2. Contents Introduction Experimental Results & discussion Summary
Room-Temperature Ionic Liquids
Solvation dynamics
Experimental
Fluorescence up-conversion
Three-pulse photon-echo peak-shift
Results & discussion
Summary
[cnpmim]+
[Tf2N]-
This slide show then ,after

3. Room-Temperature Ionic Liquids
Room-temperature ionic liquids (RTILs) are organic molten salts
Ultralow volatility:揮発性
Flameproof
Electrochemical stability
High viscosity
Application for the Electron Microscope
emim（CF3SO2）2N SEM:scanning electron microscope
Ionic liquid
Star sand SEM image
left:with RTIL right:bulk

4. Solvation dynamics Solvation in conventional liquids Stabilization hν
通常の有機溶媒 hν hν
Stabilization
Exited state
Ground state
strongly solvated

5. Solvation dynamics Solvation in ionic liquids hν emission ○:anion
Dynamic Stokes-shift
Solvation hν
emission
Solvation in ionic liquids
○:anion
●:cation

6. Fluorescence up-conversion
sample
BBO ωe ωf ωg ωs
delay
mono
chr.
PMT
ωｓ= ωｆ＋ωｇ
Exitation
Gate
Intensity
time
delay
Excitation pulse : ωe
Fluorescence : ωf
Gate pulse : ωg
Sum frequency : ωs= ωf+ ωg
BBO:β-BaB2O4
monochr:モノクロメーター（分光器）
PMT:光電子増倍管
Photomultiplier tubes

7. Three-pulse photon-echo peak-shift
―:-k1+k2+k3
―: k1-k2+k3
T　→　large
pulse1 makes the coherence of polarization.
pulse2 interferes with pulse1 indeced polarization.
pulse3 is diffracted as the signal.
Tが長くなると書き込んだ情報の劣化によってピークシフトが小さくなる
τ’　→　small
τ=0：Transient Grating 　　　　　→ 　no echo
τ≫0：decoherent　　　　　　　　 → 　no echo
T≫0：vanish diffraction fringe　 → 　no echo
3PEPS results
τ’　vs　T
干渉縞

8. Fluorescence up-conversion
[pmim]+
[cnpmim]+
[Tf2N]-
Coumarin153 in[cnpmim+][Tf2N-]
and[pmim+][BF4-]
Steady-state absorption and emission spectra
Excitation : 400nm
Response function : 230fs
Dynamic red shift
Red : rise
Blue : decay
Fluorescence time profiles

9. Fluorescence up-conversion
Dynamic red shift
Missing red shift
4600cm-1
Reconstructed time-dependent emission spectra
600cm-1
500cm-1
Too small peak shift change
　→　ultrafast component?
Time dependence of the emission band maximum

10. Three-pulse photon-echo peak-shift
in ionic liquid
in ehtanol
molecular vibration
inertial part
3PEPS results
溶媒の平均自由行程内
分子振動
Indocyanine green in[cnpmim+][Tf2N-]
and ethanol
Excitation : 800nm
Pulse duration : 15fs
Differ from Stokes-shift measurements
全体の形は似ている　200fs,400fsあたりに分子振動によるビートが見える　RTIL中 では高いところから始まり、減衰が遅い
Inertial part: Signal starts at a higher level
and decays slower in ionic liquids

11. Summary
The dynamic Stokes shift of coumarin 153 in Room temperature ionic liquids(RTILs) has been measured using fluorescence up-conversion techniques with a response function of 230fs.
Three-pulse photon-echo peak-shift(3PEPS) experiments on indocyanine green in RTILs has been measured.
Ultrafast solvation in RTILs which could not be observed by fluorescence up-conversion was suggested from 3PEPS results. Improved 3PEPS may find farther information.

12. conventional solvents
My experiment
―[bmim+][Tf2N-]
―[hmim+][Tf2N-]
―MeOH
[bmim+]
[Tf2N-]
[hmim+]
ox4 Cr:F 長時間領域　拡散と関係
Oxazine4
conventional solvents
RTILs

13. Time-zero estimation
approximation t
t=0
Time-zero
Apolar